class: center, middle, inverse, title-slide # Choropleth for continuous variables --- layout: true <div class="dk-footer"> <span> <a href="https://rfortherestofus.com/" target="_blank">R for the Rest of Us </a> </span> </div> --- class: center, middle, dk-section-title background-image:url("https://images.pexels.com/photos/7135077/pexels-photo-7135077.jpeg?auto=compress&cs=tinysrgb&dpr=2&h=750&w=1260") background-size: cover # Choropleth of continuous variables --- # Continuous variable choropleth .pull-left[ <center> <img src='images/gg_london_school_leavers_colorbar.png' width='700px'/> </center> ] -- .pull-right[ <center> <img src='images/gg_london_school_leavers_binned.png' width='700px'/> </center> ] --- ## NA values and continuous choropleth .pull-left[ To label NA values in continuous choropleth we need to go through 3 steps: - Find an unused aesthetic in the chart (the NA aesthetic) - Override the guide for the NA aesthetic - Set the `na.value` in the fill scale ] .pull-right[ <center> <img src='images/gg_london_school_leavers.png' width='100%'/> </center> ] --- ### Find an unused <span style='color:#c03728'>aesthetics <svg aria-hidden="true" role="img" viewBox="0 0 512 512" style="height:1em;width:1em;vertical-align:-0.125em;margin-left:auto;margin-right:auto;font-size:inherit;fill:#c03728;overflow:visible;position:relative;"><path d="M160 288h-56c-4.42 0-8-3.58-8-8v-16c0-4.42 3.58-8 8-8h56v-64h-56c-4.42 0-8-3.58-8-8v-16c0-4.42 3.58-8 8-8h56V96h-56c-4.42 0-8-3.58-8-8V72c0-4.42 3.58-8 8-8h56V32c0-17.67-14.33-32-32-32H32C14.33 0 0 14.33 0 32v448c0 2.77.91 5.24 1.57 7.8L160 329.38V288zm320 64h-32v56c0 4.42-3.58 8-8 8h-16c-4.42 0-8-3.58-8-8v-56h-64v56c0 4.42-3.58 8-8 8h-16c-4.42 0-8-3.58-8-8v-56h-64v56c0 4.42-3.58 8-8 8h-16c-4.42 0-8-3.58-8-8v-56h-41.37L24.2 510.43c2.56.66 5.04 1.57 7.8 1.57h448c17.67 0 32-14.33 32-32v-96c0-17.67-14.33-32-32-32z"/></svg></span> in the chart The <span style='color:#f5c04a'>continuous fill guides</span> **do not have space** for an NA label. -- We need to create a new <span style='color:#f5c04a'>guide</span> - which means we need to choose an <span style='color:#c03728'>NA aesthetic</span> Good choices include: - shape - alpha --- ### Override the <span style='color:#f5c04a'>guide <svg aria-hidden="true" role="img" viewBox="0 0 640 512" style="height:1em;width:1.25em;vertical-align:-0.125em;margin-left:auto;margin-right:auto;font-size:inherit;fill:#f5c04a;overflow:visible;position:relative;"><path d="M497.941 225.941L286.059 14.059A48 48 0 0 0 252.118 0H48C21.49 0 0 21.49 0 48v204.118a48 48 0 0 0 14.059 33.941l211.882 211.882c18.744 18.745 49.136 18.746 67.882 0l204.118-204.118c18.745-18.745 18.745-49.137 0-67.882zM112 160c-26.51 0-48-21.49-48-48s21.49-48 48-48 48 21.49 48 48-21.49 48-48 48zm513.941 133.823L421.823 497.941c-18.745 18.745-49.137 18.745-67.882 0l-.36-.36L527.64 323.522c16.999-16.999 26.36-39.6 26.36-63.64s-9.362-46.641-26.36-63.64L331.397 0h48.721a48 48 0 0 1 33.941 14.059l211.882 211.882c18.745 18.745 18.745 49.137 0 67.882z"/></svg></span> for the NA aesthetic Now that we've created an aesthetic and corresponding guide, we need to override the aesthetics: ```r gg_chart + guides(shape = guide_legend(override.aes = list(fill = "pink"))) ``` --- ### Set the `na.value` in the fill scale While the continuous fill guides don't have space for a *label* they do allow us to set an `NA` *color*: ```r gg_chart + scale_fill_viridis_c(na.value = "pink") ``` --- class: inverse # Your turn .pull-left[ Use the `your-turn.R` script in `02_07` to build this map. You'll need to add a guide item for District of California which has an NA value. - Create an NA aesthetic - Override the guide aesthetics - Set the `na.value` for the fill aesthetic ] .pull-right[ <!-- --> ]